Somewhere near the middle of "Full Metal Jacket," the sardonic protagonist Private Joker (Matthew Modine) is asked by a disdainful colonel why he wears a peace symbol on his flak jacket and has "Born to Kill" written on his helmet. Joker's answer? "I think I was trying to suggest something about the duality of man." This detail is not unimportant: "Full Metal Jacket" and almost everyone in it are split right down the middle.

The movie is formally split: Its first half unfolds at Parris Island, where clueless "maggots" are hammered on the anvil of military training until they are forged into human weapons; its second half is set before and after the Tet Offensive in Vietnam, where many of the bits of business in the first half pay off. Stanley Kubrick didn't just make a war movie; he made a philosophical inquiry into the birth of killers -- which is presented here as man coming to grips with the Jungian Shadow.

If that makes Full Metal Jacket sound stodgy and dull, it certainly isn't. Kubrick was an entertainer as well as an artist, and the film's first section comes as close to pure comedy as his double whammy of Lolita and Dr. Strangelove in the '60s. Indeed, much of the movie reads as a bizarre conflation of those earlier classics: sex and violence, violence as sex. "This is my rifle, this is my gun," the recruits' drill sergeant Hartman (Lee Ermey) bellows, grabbing his crotch on the word gun; "This is for fighting, this is for fun," the maggots call back. The recruits are trained to embrace the permanent hard-on of a rifle: As long as you are a Marine with a gun, you will never be flaccid. The homoerotic tone of the training sequences is also unmistakable. Lined up with shaved heads, the recruits look like stiff dicks, with Hartman always shoving his loudly open mouth into their faces. The entire experience seems driven by a violent terror of homosexuality and femininity, in this spotless white place where young men sleep in close quarters, shower together, shit together.

Lee Ermey has given subtler performances since (he was nicely quiet in Dead Man Walking and Seven), but his relentlessly antagonistic turn as Sgt. Hartman gave him instant cult status he dines out on to this day (hosting the military show Mail Call, presiding over talking-doll replicas of himself). Hartman is a clown, but a clown who bites. His initial browbeating of the pathetic Pyle (Vincent D'Onofrio), who can't keep from smirking at the drill instructor's elaborate invective, is hideously funny because we wouldn't be able to keep a straight face either. Then Hartman cuts Pyle's laughter off (along with his oxygen), and ours, too. Under Hartman's pitiless tutelage, Pyle gradually becomes a competent recruit but also subhuman. The implication is that this is the obvious trade-off, though others in the same batch of recruits -- Joker and his buddy Cowboy (Arliss Howard) -- manage some intellectual detachment from the process and retain some humanity. Pyle doesn't; he becomes what the Marine Corps wants -- a perfect sociopath "married to his piece."

After the first section -- a prologue promoted to Side A of an album -- the movie becomes anecdotal, with analogues of the boot-camp characters popping up everywhere. Nobody in Vietnam is as dominant as Hartman, but we're given a rather lackadaisical authority figure, a lieutenant who edits Stars and Stripes and sends reporter Joker off to cover Tet with cheesedick photographer Rafterman (Kevyn Major Howard) in tow. Kubrick plays with military language here -- a new directive encourages reporters to replace "search and destroy" with "sweep and clear" ("Very catchy," snarks Joker). Pauline Kael's review complained that the Marines' "language is inert," but the dialogue here is another instance of Kubrick's fascination with "phatic speech" -- verbiage with no content. A lot of the dialogue is just callow boasting, especially when Joker meets Pyle's Vietnam twin, Animal Mother (Adam Baldwin), and pretty much distrusts him on sight. (The brutal Animal Mother, who resembles a harder Pyle, is what Pyle might have become if he had survived the Island.)

Full Metal Jacket gathers tension in a cruelly mathemetical sequence foreshadowed by Hartman's earlier praise of infamous Marine-trained snipers -- Whitman, Oswald -- who showed what one motivated Marine and his rifle could do. The platoon has made a wrong turn; acting doesn't get any finer than Arliss Howard and Dorian Harewood (as the ironic Eightball) looking at a map and realizing how far off they are. One by one, men scamper over the treacherous rubble of Hue and get picked off ignominiously. Kubrick summons up whispers of the uncanny here, as if the god of war himself is reaching down and unplugging these robots of combat. There is a face-off mirroring the final one between Joker and Pyle, only this time Joker does not "hesitate in the moment of truth."

Coming as it did after Oliver Stone's Platoon, and after seven years of silence from Kubrick himself, Full Metal Jacket couldn't help but disappoint critics, none of whom really seemed to get it. Some turned to Gustav Hasford's more emotionally transparent source novel, castigating Kubrick for yet another icy view of humanity.

Kubrick, it was said, painted portraits of inhumanity by denying his characters their humanity. But there is humanity here, though not the sort we generally like to face. It is humanity as flawed system -- the faulty meat run through the grinder of war. Hartman reigns over his enclosed kingdom of recruits, but he's not getting them ready for war. He's getting them ready for death.